1) Field of the Invention
The present invention relates to a data distribution method, a computer program, and a data distribution apparatus that distribute data for a fee, via a network such as the Internet.
2) Description of the Related Art
Conventionally, since it is premised that data distribution services are provided to an unspecified number of clients via a network such as the Internet, the data distributed by such services include information that is obviously not necessary, i.e., noise, to the clients. For example, the patent information database available over the Internet includes information about patents in various fields, such as livingware, electrical appliances, or chemistry, and is stored in the database.
In the fee-based data distribution services provided over the Internet, the receiver of the service is charged at a metered rate. Such a technique is disclosed in Japanese Patent Application Laid-open No. H10-293621.
Thus, conventionally, although the clients are interested in information related to a specified field (hereinafter, “main field”) they have to receive information related to various other fields (hereinafter, “noise field”) as well. For example, although a chemical manufacturer is interested in information related to the chemical field of the patent classification (IPC), the patent database includes information related to various other fields. Thus, the client is mainly interested in only a part of the information in the database and may need the other information only occasionally.